Materials Data on KBe2BO3F2 by Materials Project

KBe2BO3F2 crystallizes in the trigonal R-3c space group. The structure is three-dimensional. K1+ is bonded to six equivalent F1- atoms to form distorted KF6 octahedra that share corners with six equivalent BeO3F tetrahedra and edges with six equivalent KF6 octahedra. All K–F bond lengths are 2.81 Å. Be2+ is bonded to three equivalent O2- and one F1- atom to form BeO3F tetrahedra that share corners with three equivalent KF6 octahedra and corners with three equivalent BeO3F tetrahedra. The corner-sharing octahedral tilt angles are 66°. All Be–O bond lengths are 1.64 Å. The Be–F bond length is 1.55 Å. B3+ is bonded in a trigonal planar geometry to three equivalent O2- atoms. All B–O bond lengths are 1.38 Å. O2- is bonded in a trigonal planar geometry to two equivalent Be2+ and one B3+ atom. F1- is bonded in a distorted single-bond geometry to three equivalent K1+ and one Be2+ atom.